One of the main purposes of hijab is so males don't go "crazy" looking at females. 1. If a female is wearing a shiny, colorful headscarf with tight clothes - she's not doing hijab. Males can and will find this female to be "sexy", "beautiful", etc, just as much as they would find a female who was half uncovered to be all of that. 2. If a female is wearing loose clothes with a dull colored scarf but her face shows, a male ends up looking at the face and finds it to be beautiful and it gets stuck in his head and it makes him think more about this female in an inappropriate manner - she's not doing hijab properly. Same principle applies if she is attracting attention by wearing loose but colorful, attention-attracting clothes, and also in other ways such as having colorfully painted nails, wearing provocative shoes, etc. 3. If a female is wearing a completely black, loose burqa with niqab and everything, and she has not done anything whatsoever to attract attention from males... The only parts of her body which show are hands and eyes, and even those just barely. Now you get a male saying something like "wow her hands are so pretty, she must be beautiful", or "it seems to me there's a nice body hidden behind that burqa"; well, then, as a Scholar said while giving a bayan at our local Masjid recently, these are people who shaytaan is riding hard and they are not able to rid themselves of shaytaan for even a single moment. In this situation, the female has done what she can to protect her modesty and not attract the wrong kind of attention, and the blame is on the male alone. In the first 2 situations, while there is certainly blame on the male who chooses to keep looking at the female instead of guarding his gaze and trying to rid himself of inappropriate thoughts, the blame is also shared by the female because she provoked the male to produce this response, when she could have done more to prevent it. In situation # 2, it's very possible that the female may not realize this is happening and she may be naive about it, and maybe she would do even more to cover herself if she knew that guys are still getting "turned on" by her. However, in situation # 1, this female is no different than any other immodest type female who walks around the streets wearing skimpy clothes so guys will "check her out". The female in situation # 1 has no excuse. In the last situation, the female has seemingly done the most which can be done, and has not done anything to attract attention to provoke such a response from the male. In this situation, the blame would be completely on the male and the female would be clear of any blame. The above are my personal opinions and I am not a scholar. Allah knows best.